Load advice .308 win

[earplay]

Yea, I run mainly Lee gear, and some of it is pretty junky, but seems to produce surprisingly good ammo. I think I will persevere with it for a bit, but an upgrade may be neccessary in the near future...

 

[backwoods83]

Well when you upgrade I reccomend either an rcbs small base circle fl die or forester body die, and get a redding type S bushing neck die set with a micrometer seating die, just a thought if you plan to master the 308 and do a pile of shooting. Also large quanities of lake city once fired match brass can be had for cheap and is very good brass and you can get the same velocity with 2.5-3grns less powder because they have less capacity.

 

[earplay]

Ok, will look into those options. I am at the other end of the world here in NZ, so I think our brass options are a bit more limited. Winchester is at least relatively cheap and reliable.

 

[earplay]

Well I finally got out to test 45gn Varget (AR2208) loads. Accuracy was average (around 1 MOA, 3 shots) and velocity was low, still around 2550fps. Fortunately I received a new batch of powder, and loaded a 4 rounds up to compare.

First round of the new powder 2650fps... then all 4 rounds into a fairly decent group. Was pretty happy to say the least. My one admission is however, I also increased OAL to 2.820 from 2.800 on the new rounds. So maybe that helped accuracy, but would have decreased pressure/velocity if anything I would think.

I then went back to 200m, and used up the rounds of the old powder to get rid of them. The other pic is the last round I fired at 200m.

So my conclusion to this saga is... I had a poor batch of AR2208 to start with, and the new batch seems to be on the money. Can't wait to load up some more and test them.

For reference load shown in picture is....

45gn AR2208 (Varget)
2.820 OAL
Win brass (twice fired)
178gn Amax
Fed 210 LR primers
4 shots, 100m.

This is a max and compressed load... I worked up from 43gn and have had no issues, but anyone else will need to do the same.

Matt

 

[jamesmc2]

Actually increasing the COAL can increase velocity as the bullet is close to the lands and there is less bullet jump (momentum) as the bullet engages the riflings. That is a reason (along with accuracy) that some shooters jam the bullet into the lands, it allows them some extra pressure and thus velocity. Not advisable if you plan on using your rounds for hunting as it makes cases hard to extract from the chamber. In this case where you already have a max/compressed load you may not want to increase COAL any further.

Great results by the way! There are always some speed bumps on the way to finding a good load. Looks like you found the sweet spot! Once you have found that sweet load leave well enough alone get to know how it performs at longer ranges. The velocity you are getting now should give you excellent results.

 

[earplay]

Yea I thought pressure wasn't increased until actually jamming into the lands? My Rem has a super long throat so I am miles away... Not fully sure on that one though.

Definitely keen to test further

 

[jamesmc2]

In general velocity increases as you get closer to the lands starting at about 0.25 inches from the lands. It increases more rapidly the closer you get to the lands. The link below has a graph from Speer or Berger which shows the relationship of distance from lands and pressure (velocity).

Effects of OAL on velocity? - TheFiringLine Forums

 

[earplay]

Ok, that would kinda make sense. I knocked up a dummy round to get an idea of the length I had to play with and it was coming back at about 2.95 OAL to reach the lands with the 178gn A-Max.

From scouting around the net, this seems quite common in the Rem 700's. So I am unsure increasing OAL from 2.800 to 2.8200 would cause a velocity increase in this rifle.

 

[jamesmc2]

Probably not much difference that far out. I have a factory savage and COAL to get you to the lands is 2.84"

 

[earplay]

Yea, at first measure I was thinking I had ended up with some crazy manufacturing defect, but upon further net searching it seems quite common, on the new Rems at least. Apparently they are designed to accomodate the 190gn SMK's or something?

Apparently the firing pin housing is also 'designed' to crater the primers...

The net is great for either setting your mind at ease, or making you more paranoid than ever

 

[earplay]

Well after running the 45gn of Varget behind the 178gn Amax I am getting good accuracy and velocity around 2650fps which is in line with reloading data.

I am however getting some flattening of primers (Fed 210). It is evident with primer in case and when removed. There are no other pressure signs that I can see. I am unsure whether to run with this load or back off for peace of mind. It is summer here at the moment so the temp won't be increasing a lot further.

 

[backwoods83]

As for the cratering, you can probably mark that up as a sloppy remington chamber (excessive headspace causing primer flow) if I were you id load .005" short of the mag length which should be either 2.855" or 2.875" then come up a couple tenths in powder charge to maintain the same charge density. I wouldn't worry about flattening 210 primers, they have a soft anvil, if you want peace of mind with that switch to CCI BR2s and it most likely won't flatten them.